1. Field of the Invention
The present invention relates to a digital television receiver.
2. Description of the Prior Art
In a multi-channel digital satellite broadcasting (CS broadcasting) system using CS (Communication Satellite) which has been started in recent years, a lot of (for example, 100 or more) channels are prepared, and a lot of programs are provided.
In such broadcasting, there are functions which have not been so far seen. For example, guide information relating to programs which are being currently broadcast and programs which will be broadcast in the future, together with original program data, are transmitted at predetermined time intervals, and a viewer can select and view the program on the basis of the program guide (electronic program guide [EPG]) information.
In such a digital television receiver, a ROM whose contents cannot be generally rewritten has been employed as a program ROM. For convenience of a CS broadcasting form, it is prescribed that a rewritabie ROM is mounted as a program ROM (hereinafter referred to as a program memory) as a standard in order to change the specification thereof and improve the function thereof.
When the rewritable program memory is mounted on the digital television receiver, it is possible to rewrite the contents of the program memory by sending a rewriting program by a broadcast wave.
When the power is shut off on the basis of a power failure or the power is shut off on the basis of a user operation while the contents of the program memory are being rewritten utilizing the broadcast wave, however, a program for a control portion in the receiver is not normally rewritten. Accordingly, the contents of the program memory must be rewritten by a repairing person.
When the control portion is reactivated upon normal completion of the rewiring of the program, the structures of data stored in a non-volatile data area change depending on the program which has been rewritten. Therefore, the data structures must be manually reset.